Spark plugs

does anyone know why Toyota uses denso spark plugs in one side and ngk on the other in the 4L v6?

 

They are put in that way from the factory. Two different spark plug suppliers, and they use both when assembling the engine.

 

Never been a definite answer.
Best theory is to keep suppliers happy.
Next is that each head is built at different plants.

Either way, I prefer the Denso in my 4stoke engine vehicle.

NGK in my 2 Stroke small engines.

 

Is there anything to do with performance? Just seems odd

 

All six of mine are now Denso.
I can not tell any performance difference.

 

I just changed mine and noticed. First time they were changed. 250000 km on them. They looked pretty sad.

 

here they are

 

Good job

You’ll probably catch some flack from people on here, since you went to long before changing them.
You’ll be fine. I wouldn’t recommend going that long again though

 

Yes, that is very sad. If you put that many km on without maintenance, you should be ashamed.

 

Would it help if I said that I just saved it from going to the auto boneyard and am restoring it?

 

I'm not gonna pile on.... that would be toooooo easy. Good on ya for changing them!

 

Holy smokes are those worn. How many miles on that motor?

 

Way too many! He posted 250000 km which is about 155k miles.

 

Yes. as I said earlier IF you......

 

Toyota went all-Denso with 3rd gen V6 and look what happened?